| 1 | HAO | Holland Aero Leasing B.V. | Callsign: Aerolines, ICAO callsign changed to Tulip. | NL | AVCODES |
| 2 | HAO | Holland Aero Leasing B.V. | IATA: SE, Callsign: Tulip, ICAO callsign changed from Aerolines. | NL | AVCODES |
| 3 | HAO | Harty Aviation | Callsign: Harty, | ET | AVCODES |
| 4 | HAOC | HUNTER-ASH OIL CO INC | | | SCAC4 |
| 5 | HAOI | HARRIS OIL COMPANY INC | | | SCAC4 |
| 6 | HAOS | HAGELAND AVIATION SERVICES INC | | | SCAC4 |
| 7 | HAOT | HARGIN TRANSPORT LLC | | | SCAC4 |
| 8 | HAOY | HAWKINS OIL COMPANY OF LA GRANGE IN | | | SCAC4 |
